This project seeks to elucidate the mechanisms by which oral perceptual experience is generated. Since objective measurement of the various aspects of oral experience is fundamental to this effort, the selection and refinement of appropriate psychophysical methods is a primary and continuing project concern. Currently, the routine assessment of taste is carried out using aqueous solutions representing each of the four basic tastes. Measures include both (detection) thresholds and judgments of intensity for taste stimuli at higher, more commonly encountered levels of strength. Assessments of sensitivity to localized taste and touch on the tongue and to variation in the temperature or viscosity of an oral bolus are also available. Olfactory function is routinely assessed by a standardized test of odor identification. These methods are used to study oral sensory changes that may occur with oral or systemic disease and its treatment, with salivary gland dysfunction, with aging or in association with an isolated oral or taste complaint. Such studies can provide insight in the sensory mechanisms that normally provide for the perception of the complex oral stimuli encountered in everyday life but may, in other circumstances, produce distressing and debilitating oral symptoms.